Sign up to receive free email alerts when patent applications with chosen keywords are publishedSIGN UP

Abstract:

The invention includes a method of preparing hypochlorite-activated
solutions of hypobromous acid and/or hypobromite ion. The method includes
the steps of mixing a solution of a source of bromide ion with a solution
of a source of hypochlorite ion to activate the bromide ion, allowing
sufficient time to maximize the activation of the bromide ion, and
storing the solution before use. The invention also includes a method of
using the solution to wash meat and poultry carcasses, trim, and offal to
reduce pathogenic microorganisms. The solutions may also be used to
reduce pathogenic microorganisms in industrial cooling water and on food
contact hard surfaces and equipment. The solutions may be stored for up
to about three hours before use and are stable for that period of time.

Claims:

1. A method of introducing a biocidally effective dose of hypobromous
acid and hypobromite ion into water used to wash meat and poultry
carcasses, trim, and offal for the reduction of pathogenic
microorganisms, comprising: (a) Mixing a solution of a source of bromide
ion with a solution of a source of hypochlorite ion to activate the
bromide ion and to form a solution selected from the group consisting of
hypobromous acid, hypobromite ion, and a mixture of both hypobromous acid
and hypobromite ion; (b) Allowing sufficient time to maximize the
activation of said bromide ion into said solution selected from the group
consisting of hypobromous acid, hypobromite ion, and a mixture of both
hypobromous acid and hypobromite ion; (c) Storing said solution selected
from the group consisting of hypobromous acid, hypobromite ion, and a
mixture of both hypobromous acid and hypobromite ion for subsequent use;
and (d) Introducing said stored solution to water used to wash meat and
poultry carcasses, trim, and offal for the reduction of pathogenic
microorganisms.

2. A method of introducing a biocidally effective dose of hypobromous
acid and hypobromite ion into industrial cooling water for the reduction
of pathogenic microorganisms, comprising: (a) Mixing a solution of a
source of bromide ion with a solution of a source of hypochlorite ion to
activate the bromide ion and to form a solution selected from the group
consisting of hypobromous acid, hypobromite ion, and a mixture of both
hypobromous acid and hypobromite ion; (b) Allowing sufficient time to
maximize the activation of said bromide ion into said solution selected
from the group consisting of hypobromous acid, hypobromite ion, and a
mixture of both hypobromous acid and hypobromite ion; (c) Storing said
solution selected from the group consisting of hypobromous acid,
hypobromite ion, and a mixture of both hypobromous acid and hypobromite
ion for subsequent use; and (d) Introducing said stored solution to
industrial cooling water for the reduction of pathogenic microorganisms.

3. A method of introducing a biocidally effective dose of hypobromous
acid and hypobromite ion into water used to reduce pathogenic
microorganisms on food contact hard surfaces and equipment, comprising:
(a) Mixing a solution of a source of bromide ion with a solution of a
source of hypochlorite ion to activate the bromide ion and to form a
solution selected from the group consisting of hypobromous acid,
hypobromite ion, and a mixture of both hypobromous acid and hypobromite
ion; (b) Allowing sufficient time to maximize the activation of said
bromide ion into said solution selected from the group consisting of
hypobromous acid, hypobromite ion, and a mixture of both hypobromous acid
and hypobromite ion; (c) Storing said solution selected from the group
consisting of hypobromous acid, hypobromite ion, and a mixture of both
hypobromous acid and hypobromite ion for subsequent use; and (d)
Introducing said stored solution to water used to reduce pathogenic
microorganisms on food contact hard surfaces and equipment.

4. The method of claim 1, wherein said solution of a source of bromide
ion is sodium bromide solution.

5. The method of claim 1, wherein said solution of a source of
hypochlorite ion is sodium hypochlorite solution.

6. The method of claim 1, wherein the mole ratio of the source of bromide
ion to the source of hypochlorite ion is between 1:1 and 1:2.

7. The method of claim 1, wherein up to 18 minutes is allowed to maximize
the activation of said bromide ion.

8. The method of claim 1, wherein said storing is for a period of time up
to three hours.

9. The method of claim 1, wherein said stored solution is stable for up
to three hours.

10. The method of claim 1, further comprising introducing additional
water in step (a).

11. The method of claim 1, further comprising, after step (d), lowering
the pH of said water used to wash meat and poultry carcasses, trim, and
offal.

12. The method of claim 3, further comprising, after step (d), lowering
the pH of said water used to treat food contact hard surfaces and
equipment.

Description:

CROSS-REFERENCE TO RELATED APPLICATION

[0001] Pursuant to 35 U.S.C. §120, this application is a
continuation-in-part of and claims priority to co-pending U.S. patent
application Ser. No. 12/658,916 filed on Feb. 16, 2010, the entire
disclosure of which is incorporated herein by reference.

BACKGROUND OF THE INVENTION

[0002] 1. Field of the Invention

[0003] The invention relates to methods and compositions for reducing
pathogenic microorganisms on meat and poultry carcasses, trim, and offal,
in industrial cooling water, and on food contact hard surfaces and
equipment.

[0004] 2. Description of the Related Art

[0005] The use of sodium bromide in conjunction with a source of sodium
hypochlorite bleach to generate a hypobromous acid biocide for the
treatment of cooling water has been a standard practice for decades.
There are three existing methods for making biocidal solutions of
hypobromous acid and/or hypobromite ion for the treatment of cooling
water.

[0006] First, the major supplier of sodium bromide (BWA Additives)
recommends a process of directing makeup water, sodium bromide, and
sodium hypochlorite solutions to a residence tank. Water Front Product
Information. LiquiBrom®3800--LiquiBrom 4000--LiquiBrom
4300--LiquiBrom 4600. Cost Effective Bromine Source for Microbiological
Control in Industrial Water Treatment. Published by BWA Water Additives,
2006. Upon activation or oxidation of the bromide (Br.sup.-) ion to
hypobromous acid and/or hypobromite ion (HOBr/OBr.sup.-), the mixture is
immediately introduced to the cooling water to be treated. This reference
states that the maximum concentration of activated HOBr/OBr.sup.- that
can be achieved is 2500 ppm expressed as Cl2 (or 5625 ppm expressed
as Br2). This reference teaches that any attempt to increase the
concentration of activated HOBr/OBr.sup.- to more than 2500 ppm expressed
as Cl2 (or 5625 ppm expressed as Br2) would simply be a waste
of bromide ion.

[0007] The second method, disclosed in U.S. Pat. No. 4,451,376, involves
feeding sodium bromide and sodium hypochlorite solutions to a common tee
before directing the mixture into the recirculating cooling water. Both
the first and second methods require the immediate addition of the
activated solution to the cooling water to be treated based on the
widely-held belief that the activated solution is unstable and quickly
loses activity due to HOBr/OBr.sup.- decomposition.

[0008] The third method, described in U.S. Pat. No. 5,208,057, requires
introducing sodium bromide and sodium hypochlorite independently to the
cooling water so that the activation of Br.sup.- ion by hypochlorite
occurs over time, under more dilute conditions in-situ. The '057 patent
discloses the use of the in-situ method of activating Br.sup.- ion to
HOBr for disinfection action during the butchering and processing of
fowl. The '057 patent describes the introduction of a source of Brion to chicken chill or scald tank water followed by the separate
addition of an oxidizing agent for activation.

[0009] All three methods generally employ a molar excess of sodium
hypochlorite over sodium bromide because it has been assumed that excess
hypochlorite re-oxidizes bromide ion into HOBr/OBr.sup.-. The activated
HOBr/OBr.sup.- forms in the bulk cooling water. The amount of each
activated species formed is dependent on the pH of the bulk water.

[0010] In the preparation of biocides, it is very important that the
chemical reactants be utilized as efficiently as possible in order to
conserve raw material costs. The problem with the existing methods is
that they require the biocide to be prepared immediately before it is
added to the water to be treated, rather than being prepared in advance
and stored, because of the presumed instability of the activated
solution. This results in waste of the reactants and inefficiency in
preparation, which increases the cost of the biocide program.

[0011] The prior art does not disclose the efficiency of the various
methods employed for treatment of industrial cooling water with respect
to the percent conversion of sodium bromide into HOBr/OBr.sup.- ion and
the percent utilization of sodium hypochlorite. The prior art also does
not teach that sufficient time be allowed for the hypochlorite source to
activate Br.sup.- ion and maximize the conversion of Br.sup.- into
HOBr/OBr.sup.-. Further, the prior art does not disclose the rate at
which Br.sup.- ion is activated under the different conditions.

[0012] Thus, there is a need for a method for preparing a stable
hypochlorite-activated solution of HOBr/OBr.sup.- ion that efficiently
converts Br.sup.- ion and significantly utilizes NaOCl, and results in a
product that can be stored for use throughout a working day.

SUMMARY OF THE CLAIMED INVENTION

[0013] An embodiment of the invention overcomes one or more of the
problems with the known prior art by providing a method of preparing
hypochlorite-activated solutions of HOBr/OBr.sup.- ion that are efficient
to prepare, may be stored, and can be used for the reduction of
pathogenic microorganisms in water used to wash meat and poultry
carcasses, trim, and offal; industrial cooling water; and water used to
sanitize food contact hard surfaces and equipment. In one embodiment, the
method includes mixing a solution of a source of bromide ion with a
solution of a source of hypochlorite ion to activate the bromide ion and
to form a solution selected from the group consisting of hypobromous
acid, hypobromite ion, and a mixture of both hypobromous acid and
hypobromite ion; allowing sufficient time to maximize the activation of
the bromide ion into the solution selected from the group consisting of
hypobromous acid, hypobromite ion, and a mixture of both hypobromous acid
and hypobromite ion; storing the solution for subsequent use; and
introducing the stored solution to water used to wash meat and poultry
carcasses, trim, and offal, to industrial cooling water, or to water used
to sanitize food contact hard surfaces and equipment, for the reduction
of pathogenic microorganisms. The resulting solutions can be stored for
up to about three hours before being used.

BRIEF DESCRIPTION OF THE DRAWINGS

[0014]FIG. 1 is a schematic representation of a system used to
continuously prepare a solution of hypobromous acid (HOBr) in a
controlled manner according to the method of the invention.

[0015]FIG. 2 is a graph showing the decay of HOBr from
1,3-dibromo-5,5-dimethylhydantoin (DBDMH) compared to HOBr from
NaOCl-activated HBr solution (600 ppm as bromine).

[0016]FIG. 3 is a graph showing the stability profile of hypobromous acid
as bromine.

[0024]FIG. 11 is a graph showing the HOBr/OBr.sup.- ion generation and
stability profile in cooling water for 1:2 NaBr:NaOCl mole ratio showing
depletion of excess chlorine.

DETAILED DESCRIPTION OF THE INVENTION

I. Analytical Methods Used

[0025] In the examples set forth below, references are made to an
iodometric titration, a N,N-diethyl-p-phenylenediamine (DPD) Total
Halogen Colorimetric Method and a DPD Differentiation Colorimetric Method
(also known as the Palin Modification). These methods were used to
quantify and/or differentiate halogen levels for the microbiology and
storage stability studies, which are now presented. Each method is
described in detail below.

[0026] A. Iodometric Titration Method

[0027] The iodometric titration is a technique that allows for the
determination of the total halogen present in any given system and is
usually the method of choice when concentrated halogen solutions are
prepared. This technique does not allow for the differentiation between
the halogens e.g. how much is present as bromine and how much is present
as chlorine. Therefore, the halogen levels determined by the iodometric
method are usually expressed in terms of "as chlorine" or "as bromine"
even though the system may contain a mixture of both bromine and
chlorine. A typical iodometric titration is performed as follows:

[0028] A sample of the halogen-containing solution is accurately weighed
(4 decimal places) to a beaker, then deionized water (DI) or reverse
osmosis (RO) water is added to the beaker. Using a magnetic stir bar to
ensure appropriate mixing, add approximately 5 ml of 80% acetic acid and
approximately 1 g potassium iodide crystals to the beaker. Mix the
solution and allow the potassium iodide crystals to dissolve. The
solution will turn a dark yellow/red color as the bromine or chlorine or
both, oxidize the iodide ion to liberate iodine. Under acidic conditions,
aqueous halogen-containing solutions quantitatively liberate iodine from
excess potassium iodide. The liberated iodine is titrated with a standard
solution of 0.1000N sodium thiosulfate (Na2S2O3) until the
solution turns a faint straw color. The faint straw color indicates the
titration is near its end-point. Starch indicator (1 ml of 0.5% starch)
is then introduced to the titration flask so that the solution changes
from pale straw yellow to black or dark blue. This is the color of the
complex that forms between starch and iodine. The more intense blue/black
color serves to sharpen the end-point. Continue to titrate drop by drop
until the blue/black color is completely discharged and the solution is
colorless. The volume (V) of 0.1000N sodium thiosulfate titrant required
to affect the end-point is used to calculate the activity of the
halogen-containing solution.

[0031] To express the results as weight % as Br2: [0032] Calculate
the weight % as Cl2 and multiply the result by 2.25. [0033] Example:
10.2% as Cl2=10.2×2.25=22.95% as Br2

[0034] B. DPD Total Halogen Colorimetric Method

[0035] The DPD Total Halogen Method is similar to the iodometric titration
in that it also is limited to detecting the total halogen level in an
aqueous system, but is more accurate when low levels of total halogen are
present. A typical DPD Total Halogen Method is performed as follows.

[0036] A HACH DR/700 Colorimeter (or equivalent) is utilized for the
analysis. To analyze the concentration of halogen as total chlorine on
the HACH DR/700 Colorimeter, module number 52.01 (525 nm) should be
installed and used in conjunction with HACH Method number 52.07.1. The
instrument must be set to the low (LO) range mode so that the display
reads to the hundredths place (0.00). Make an appropriate dilution with
reverse osmosis (RO) or deionized (DI) water. Fill two sample cells with
10 ml of the diluted sample. Designate one of the cells to be the "blank"
and the other to be the prepared sample. Dry the outside of both cells
with a paper towel or cloth and make sure the cells are free of
fingerprints or smudges. Cap the blank cell and place it into the cell
holder with the diamond mark facing you. Cover the cell compartment and
press ZERO. The instrument will display 0.00. Remove the "blank" at this
time. Add the contents of one DPD Total Chlorine pillow pack (for a 10 ml
sample volume) to the prepared sample cell. Cap and shake vigorously. A
pink color will develop indicating the presence of halogen. Immediately
place the sample cell in the compartment with the diamond facing you,
cover the cell compartment and press READ. The instrument display will
flash "- - - " followed by the results in ppm total chlorine.

[0037] Calculations:

[0038] Total Chlorine: no calculation needed, the instrument reading is
the ppm total Cl2.

[0039] Bromine: ppm Br2=2.25×ppm total Cl2

[0040] (Multiply the result by dilution factor in order to obtain the
halogen concentration in the parent (undiluted) solution).

[0042] In order to determine how much of the halogen is present as bromine
and how much is present as chlorine, the DPD Differentiation Method (also
known as the Palin Modification) is utilized. This method allows for the
differentiation and quantification of bromine and chlorine in a solution.
A typical DPD Differentiation Method is performed as follows.

[0043] A HACH DR/700 Colorimeter is utilized for this testing. To analyze
the concentration of halogen as free chlorine on the HACH DR/700
Colorimeter, module number 52.01 (525 nm) should be installed and used in
conjunction with HACH Method number 52.05.1. The instrument must be set
to the low (LO) range mode so that the display reads to the hundredths
place (0.00). Make an appropriate dilution. For example, testing a
theoretical 300 ppm as Br2 solution, weigh out 97.0 g distilled
water, exactly 1.00 g of solution containing the theoretical 300 ppm as
Br2, and 2.0 g of a 10% glycine solution. The diluted solution is
then well mixed in order to bind any free chlorine present into the form
a combined form of chlorine, N-chloroglycine. Fill two sample cells with
10 ml of the diluted sample containing the glycine. Designate one of the
cells to be the "blank" and the other to be the prepared sample. Dry the
outside of both cells off and make sure both cells are free of
fingerprints or smudges. Cap the blank cell and place it into the cell
holder with the diamond mark facing you. Cover the cell compartment and
press ZERO. The instrument will display 0.00. Remove the "blank" at this
time. Add the contents of one DPD Free Chlorine pillow pack (for a 10 ml
sample size) to the prepared sample. Cap and shake vigorously. A pink
color will develop indicating the presence of bromine. Place the sample
cell in the compartment with the diamond facing you, close the cover and
press READ. The instrument display will flash "- - - " followed by the
results in expressed in ppm free chlorine. This reading is designated
"B." Remove the sample cell from the compartment and add a small amount
of potassium iodide (KI) crystals (2-3 crystals) to the prepared sample
cell still containing the sample, and vigorously shake. This step allows
any glycine-bound chlorine to react with the KI, liberate iodine, which
then reacts with the DPD indicator to intensify the pink coloration.
Place the sample cell back in the compartment with the diamond mark
facing you, close the cover and press READ. The results represent total
halogen expressed as ppm free chlorine. This reading is designated "TH."

[0044] Under conditions when all the halogen is present as bromine, the
results from the first and second reading are identical, meaning there
was no color intensification when the KI crystals were added to the
prepared sample cell: TH=B.

[0045] If TH>B, then some of the halogen is present as chlorine (C)
expressed as ppm free chlorine: Therefore, C=TH-B.

[0046] Calculation:

[0047] Bromine: ppm Br2=2.25×B

[0048] (Multiply the result by dilution factor in order to obtain the
halogen concentration in the parent (undiluted) solution).

II. Definitions

[0049] The following definitions are used in this specification.

[0050] "Animal carcasses" means the dead bodies of animals, especially
ones slaughtered for food. In this context, carcasses are understood to
be the dead bodies of four-legged animals with or without hide such as
cattle and hogs and the dead bodies with or without feathers of poultry
such as chicken and turkey.

[0051] "Meat carcass" means the carcasses of beef, pork, lamb, and any
other four-legged animal that is processed for food.

[0053] "Trim" means a cut of meat or poultry, such as what is left after
primal cuts are removed from the carcass of the butchered animal. These
can be the bits trimmed off larger cuts to make them the right size and
shape for selling to the consumer and to ensure that they have the
correct amount of fat for the grade (Choice, Select, and so on). It
primarily includes trimmings off the skeleton. Trim is used to make
ground meat and further processed products such as sausage.

[0054] "Offal" means the entrails and internal organs of a butchered
animal, and generally includes most internal organs other than muscle or
bone (e.g., heart, kidneys, tongue, liver, and stomach).

[0055] "Primal cut" refers to a piece of meat initially separated from the
carcass during butchering. Primal cuts may be sold complete or cut
further into smaller sub-primal units

III. Method of Preparing Hypobromous Acid

[0056] One embodiment of the invention is a method for continuously
preparing an aqueous solution of hypobromous acid (HOBr) by mixing in
water an aqueous solution of hydrogen bromide (HBr) (i.e., hydrobromic
acid) with an approximately 1:1 stoichiometric amount of a source of
hypochlorite (i.e., each mole of HBr is mixed with approximately one mole
of hypochlorite ion from a source of hypochlorite).

[0057] Any source of an aqueous solution of HBr may be employed. A
particularly convenient source of aqueous HBr is that which is a
byproduct of organic bromination reactions used to make, for example,
brominated flame retardants. During the reaction of elemental bromine
with an organic compound such as bisphenol A, a bromine atom substitutes
for a hydrogen atom on the aromatic rings and hydrogen bromide gas is
evolved from the reactor. Hydrogen bromide gas is extremely soluble in
water and so the gas is captured with a water scrubber. On heating the
resultant solution, HBr gas is evolved (along with some water) and the
solution steadily decreases in strength until it distills unchanged at
126° C. as the constant boiling azeotrope containing 48% HBr. The
azeotropic composition may be used directly in the method of the
invention or it may be diluted 50:50 w/w with water prior to use to yield
a 24% solution of HBr which is safer to ship than 48% HBr and has less
tendency to fume corrosive HBr vapors. In addition, the 24% solution of
HBr has less tendency to undergo undesirable photochemical formation of
bromine during storage.

[0058] Another suitable source of an aqueous solution of HBr is that
formed when a solution of sodium bromide (NaBr) is mixed with a
stoichiometric amount of a strong mineral acid such as hydrochloric acid
(HCl), sulfuric acid (H2SO4) or nitric acid (HNO3) (i.e.,
each mole of bromide ion is mixed with one mole of proton (hydrogen ion)
from the mineral acid). In solution, the bromide (Br.sup.-) ions from
NaBr are fully dissociated, as are the protons and anions of a strong
mineral acid. Hence a solution of NaBr and a stoichiometric amount of
strong mineral acid is indistinguishable from a solution of HBr and the
salt of a mineral acid.

[0059] Any source of hypochlorite may be employed. It is convenient if the
hypochlorite source is commercially available as an aqueous solution such
as sodium hypochlorite (NaOCl) or potassium hypochlorite (KOCl). For
economic reasons, solutions of NaOCl are preferred. It is well known that
solutions of NaOCl are unstable at normal temperatures and degrade with
time. However, the invention does not depend on the age or activity of
the NaOCl solution. If the solution has degraded below the 12.5% NaOCl
concentration that is commonly supplied, then the end user simply has to
adjust the NaOCl delivery pump to a faster pumping rate to compensate for
the lower concentration of the degraded solution.

[0060] Solid sources of hypochlorite are also suitable for use. These
include calcium hypochlorite (Ca(OCl)2) and lithium hypochlorite
(LiOCl). For economic reasons, solid Ca(OCl)2 is preferred and may
be administered in the form granules or tablets. Water is flowed through
chemical feeder devices containing the solids. Depending upon the water
temperature, and the amount of solid product that the water contacts in
the feeder, a hypochlorite solution of a well-defined concentration exits
the chemical feeder. The actual concentration can be determined by
iodometric titration and expressed as weight % as Cl2. This permits
calculation of the HBr solution flow rate required for mixing with the
Ca(OCl)2 solution. In this way, stoichiometric amounts of HBr and
Ca(OCl)2 are continuously delivered to form the HOBr solution (i.e.,
each mole of HBr is mixed with one mole of hypochlorite ion from a source
of hypochlorite).

[0061]FIG. 1 is a schematic representation of a system used in the method
of the invention to continuously prepare a solution of HOBr. A container
of aqueous hydrogen bromide solution 105 and a container of a source of
hypochlorite, preferably sodium hypochlorite bleach, 110 were each
equipped with chemical delivery diaphragm pumps 135. Water was directed
through a flowmeter 100 and into a length of pipe where the hydrogen
bromide solution was introduced through injection point 125, and sodium
hypochlorite solution was introduced through injection point 130. The
hydrogen bromide solution and the sodium hypochlorite solution may be
added in a sequential manner with either solution first, or they may be
added to the water simultaneously through a Tee fitting. In this case,
the hydrogen bromide solution and the sodium hypochlorite solution are
introduced to the two arms of a Tee fitting and the mixture is injected
into the pipe of water. Because the dilution water flow is typically
controlled by a solenoid or valve, this method of addition can be either
continuous or intermittent depending upon the position of the flow
control valve. The water containing hydrogen bromide and sodium
hypochlorite solutions was mixed using an in-line static mixer 140. A pH
probe and meter 145 monitored the pH of the mixture and adjusted the rate
of addition of hydrogen bromide solution or sodium hypochlorite solution
through a pH controller 120 that is interfaced to the chemical delivery
diaphragm pumps 135. The mixture was then directed to a proportional
dispenser 150 set to dilute the mixture to the desired HOBr concentration
with water. The degree of dilution depends on the required concentration
of HOBr. Instead of proportional dispenser 150 a conventional diaphragm
or centrifugal pump may be used to effect the desired dilution provided
the volumetric flows rates of the dilution water and activated solution
are known.

Examples 1-3

[0062] The apparatus represented in FIG. 1 was used to continuously
generate solutions of HOBr that were close to 300 ppm (as Br2). The
results are shown in Table 2.

[0063] The relative stability of HOBr derived from NaOCl-activated HBr and
HOBr derived from DBDMH was compared side-by-side. A solution of HOBr
(600 ppm as bromine) was used in the comparison because this is the
amount of bromine that typically exits the commercial DBDMH feeders when
the solid product is dissolved. The activity of the solutions was
measured using the DPD Total chlorine colorimetric method. Solutions were
stored in the dark to prevent photodegradation due to UV light exposure.
The temperature ranged from 70-75° F. for the duration of the
test.

[0065]FIG. 2 demonstrates that the presence of DMH does have a
stabilizing effect on the HOBr, but contrary to the teachings of Howarth
et. al, it is not an essential requirement for production of a solution
which might be stored several days prior to use. The half-lives of the
HOBr in the respective solutions are calculated as follows:

[0066] Graphs of ln(Co/Ct) where Co is the initial concentration of HOBr
and Ct is the concentration at day t were close to straight lines for
both the DBDMH and NaOCl-activated HBr derived solutions. (the regression
analysis correlation coefficient, R2 values were close to 1). The
R2 value for the DBDMH and the NaOCl-activated HBr solutions were
0.9251 and 0.9302, respectively. The slope for the linear regression line
for the NaOCl-activated HBr solution indicated the HOBr decayed with a
rate constant of 0.0880 day-1. The slope for the linear regression
line for the DBDMH indicated that the HOBr solution decayed with a rate
constant of 0.051 day-1.

[0067] The half-lives of HOBr from the HBr-activated solution and the
DBDMH solution were calculated by dividing the slopes of the respective
regression lines by 0.692--the natural logarithm (ln) of 2. These figures
are displayed in Table 3 below.

[0068] The previous examples (1-4) demonstrate that solutions of sodium
hypochlorite readily activate HBr to HOBr instantaneously and, depending
on the final concentration of HOBr, typically with 100% conversion. Thus,
it would be expected that all hypochlorite solutions (e.g. potassium
hypochlorite (KOCl)), would work in an identical fashion. This example
determined the efficiency of the process when solid sources of
hypochlorite, such as calcium and lithium hypochlorite, are used to
activate HBr. In this example, solid calcium hypochlorite was used to
activate HBr to determine the efficiency of bromide ion utilization and
the stability of the resultant activated solutions.

[0069] In this example, 48% HBr was activated using three different
techniques of using solid calcium hypochlorite (70% expressed as
Cl2). Techniques 1 and 2 utilized stoichiometric amounts of 48% HBr
and solid calcium hypochlorite (70% as Cl2) to generate a solution
of HOBr (theoretically 5000 ppm expressed as bromine). In technique 1,
48% HBr was introduced to a slurry of calcium hypochlorite in city water.
In technique 2, a calcium hypochlorite slurry was introduced to city
water containing the 48% HBr. Technique 3 is the same order of addition
as technique 2 except the amount of calcium hypochlorite (70% as
Cl2) that was introduced was based solely on the observed color
change of dark orange to bright yellow. The relative % conversion of
bromide ion into HOBr was assessed for each method, in addition to
determining the decay kinetics for each activated solution.

[0070] In the first technique, calcium hypochlorite (70% as Cl2)
(3.023 g) was added to the city water (942.0 g) to produce a slurry,
because not all the solid components in the calcium hypochlorite were
fully solubilized. Using a magnetic stir plate the slurry was mixed
gently. While mixing, the 48% HBr (5.00 g) was smoothly added to the
slurry within approximately 15 seconds. After all the 48% HBr was added,
a clear, solids-free solution was obtained. During the addition, the
mixture turned from an initial pale yellow pale color to dark orange then
to a bright yellow solution.

[0071] In the second technique, the 48% HBr (5.00 g) was introduced to the
city water (942.0 g) first. Using a magnetic stir plate the solution was
mixed gently. While mixing, the calcium hypochlorite (70% as Cl2)
(3.0224 g) was smoothly added to the solution over the course of 30
seconds. During the addition, the mixture turned from an initial pale
yellow color to dark orange and then to a bright yellow solution. No
turbidity indicative of undissolved solids was observed throughout the
activation process.

[0072] In the third technique, the 48% HBr (5.00 g) was introduced to the
city water (942.0 g) first. Using a magnetic stir plate the solution was
mixed gently. While mixing, calcium hypochlorite (70% as Cl2) was
smoothly added to the solution until the color of the solution changed
from pale yellow to dark orange to bright yellow to signal the
termination of the calcium hypochlorite addition. The amount of calcium
hypochlorite (70% as Cl2) added at this point was 2.88 g. The
calcium hypochlorite (70% as Cl2) addition took approximately three
minutes.

[0073] For all three techniques, the activated solutions were stored away
from direct UV light to prevent photodegradation during the stability
testing. The tests were performed at ambient temperature. The solutions
were initially tested using the DPD Differentiation Method (also known as
the Palin Modification) to confirm no chlorine was present after
activation. After verifying no excess chlorine was present, the solutions
were analyzed using the DPD Total Halogen Method. The results were
expressed as ppm as bromine. These results were used to determine the
percent bromide ion activated to HOBr. Then the decay profiles were used
to determine the half-lives and decay rate constants.

[0074] Graphs of ln(Co/Ct) (where Co is the initial concentration of HOBr
and Ct is the concentration at time t) plotted against time t. The
R2 values for techniques 1, 2, and 3 each plotted close to a
straight line (the regression analysis correlation coefficient, R2
value was close to 1) for all three Ca(OCl)2-activated HBr
solutions. The R2 values for techniques 1, 2, and 3 were 0.9375,
0.8609, and 0.9528, respectively. From this line the half-lives and rate
constants were determined. The half-lives were calculated by dividing the
slopes of the respective regression lines by 0.693--the natural logarithm
of 2. The slope of the respective linear regression lines indicated the
rate constant for HOBr decomposition (expressed as Br2) at each
concentration. These figures are reported in Table 4 below.

[0075] The solid calcium hypochlorite successfully activated the HBr but
subsequently the HOBr generated was not as stable as when HBr was
activated with sodium hypochlorite. The percent bromide ion conversion
into HOBr is high in all cases. However, compared to similar
concentration solutions prepared using aqueous sodium hypochlorite
solutions, the calcium hypochlorite-activated solutions degrade more
rapidly. It is noteworthy that the least efficient conversion of Brion into HOBr and the least stable activated solution was prepared when
the color transition method was used to determine the time to terminate
the Ca(OCl)2 addition. This further contrasts the method advocated
by Howarth (U.S. Pat. Nos. 5,641,520 and 5,422,126) which stated that the
observation of the color transition was the signal to cease the addition
of hypochlorite. Consequently, activation of HBr using a stoichiometric
amount of solid hypochlorite is the preferred method.

[0076] It can thus be concluded that solid sources of hypochlorite such as
Ca(OCl)2 are also suitable for activation of HBr into HOBr. Noting
that low conversion of bromide ions to HOBr represents the major chemical
cost limitation and hence the economics of the process, and for reasons
of improved storage stability, it is preferred that stoichiometric
amounts of HBr solution and solid hypochlorite are employed (i.e. each
mole of HBr is mixed with one mole of hypochlorite ion from calcium
hypochlorite).

Example 6

[0077] Another method of forming an aqueous HBr solution is through the
combination of sodium bromide and hydrochloric acid. During the first
attempt to form a theoretical 24% HBr solution, 46% sodium bromide (40.00
g) was accurately weighed to a beaker. To this, a stoichiometric amount
of 31.4% hydrochloric acid (20.78 g) was smoothly added with gentle
agitation. However, a precipitation reaction immediately occurred. The
precipitate was white and thought to be the formation of solid NaCl salt.
To the precipitated sample, sufficient reverse osmosis (RO) water (18.02
g) was added until a homogenous solution was achieved. The theoretical
concentration for the diluted solution was 18.36% HBr. The second attempt
was to prepare the 18.36% HBr solution directly, and without
precipitation by the addition of excess water before the hydrochloric
acid was introduced. The preparation of the second sample required a
stoichiometric amount of 46% sodium bromide (40.00 g), which was added to
RO water (17.6 g) and mixed. Then a stoichiometric amount of hydrochloric
acid 31.4% (20.78 g) was added to the sodium bromide and water under
gentle agitation. This produced a homogeneous solution equivalent to a
theoretical 18.46% HBr. The solution was stored in a clear container with
lid and stored at 35-40° F. for two days in the laboratory
refrigerator. The sample was determined to have no precipitate after the
two days, but a few small crystals formed after a period of 15 days at
the depressed temperature.

IV. Method of Using Hypobromous Acid to Wash Animal Carcasses, Trim, and
Offal

[0078] A second embodiment of the invention is a method of using the
resultant HOBr solutions to wash an animal carcass, animal trim, or
animal offal for sufficient time to reduce the number of microorganisms,
including human pathogenic bacteria, associated with the carcass, trim,
or offal.

[0079] The HOBr solutions prepared using the method of the first
embodiment of the invention display antimicrobial properties to
microorganisms resident on and within the animal carcass, animal trim, or
animal offal. These include spoilage microorganisms such as yeast, mold,
and fungi, but the solutions prepared by the method of the invention are
especially effective against human pathogenic microorganisms including
enteric bacteria such as E. coli O157:H7 and Salmonella typhimurium.

[0080] The animal carcasses, animal trim, or animal offal are contacted
with the HOBr solutions in any manner that permits good distribution of
the HOBr solution over the animal piece. This can be accomplished by
dipping or submerging the animal piece in a tank of HOBr solution,
subjecting the animal piece to a pressurized spray of HOBr solution, or
subjecting the animal piece to a fog of HOBr solution produced by
directing the HOBr solution through fogging apparatus. During the
dipping, submersion, spraying and fogging, the animal piece may be
subject to mechanical action through agitation or by physical scrubbing
with brushes. During spraying, the pressure of the HOBr solution spray
may be increased to further impinge the animal piece. Enhanced
impingement allows the HOBr solution to penetrate the surface of the
animal piece and attack embeddied microorganisms.

[0081] The animal carcasses, animal trim, or animal offal are contacted
with the HOBr solution for a time sufficient to effect a reduction in the
number of human pathogenic bacteria associated with the animal pieces.
Spraying may be accomplished in a dedicated cabinet in which an animal
carcass is subject to a pressurized spray (between 25 and 250 psig) for
less than one minute. Animal trim may be sprayed for less than five
seconds with a low-pressure stream of HOBr solution from a spray bar as
it moves along a conveyor belt. Most poultry processing facilities cool
the product by submerging it for 30-180 minutes in a chiller tank
containing an antimicrobial chemical. The chilled water solution is
approximately 35° F.

Example 7

[0082] Some animal carcass washing facilities prefer to directly prepare
the animal carcass wash (i.e., omitting the step of diluting a more
concentrated solution). This example determined the optimum activation
conditions in terms of the % conversion of Br.sup.- ion into HOBr, the
rate of the activation reaction, and the storage stability of the
resultant activated solution.

[0083] Direct Preparation of Ready-to-Use (RTU) Carcass Wash

[0084] The relative stability of HOBr (expressed as Br2) was compared
at three different low concentrations. The HOBr (expressed as Br2)
concentrations compared were 600 ppm, 300 ppm, and 50 ppm. The solutions
were activated separately by adding 1:1 stoichiometric amounts of HBr and
NaOCl bleach to a known amount of city water to theoretically generate
the desired concentrations, 600 ppm, 300 ppm, and 50 ppm of HOBr
(expressed as Br2). The calculated amounts are reported in Table 5.
The 48% HBr was introduced to a known amount of city water. Using a
magnetic stir plate the solution was mixed gently until homogenous. While
mixing, a stoichiometric amount of sodium hypochlorite bleach of known
activity (determined by the iodometric titration) was smoothly added to
the solution. Any color transition was noted and the final pH was
measured. The weights or volumes of reactants used to prepare the
activated solutions are reported in Table 5.

[0085] The activated solutions were shielded from direct UV light to
prevent photodegradation of HOBr during the stability testing. The tests
were performed at ambient temperature. The solutions were initially
tested using the DPD Differentiation Method (also known as the Palin
Modification) to verify that no chlorine was present after activation.
After confirming no excess chlorine was present, the solution was
analyzed using the DPD Total Halogen Method. The results were expressed
as ppm as bromine. These results were used to determine the percent
bromide that was converted to HOBr. Decay profiles for each solution were
used to determine the half-life and decay rate constant of the HOBr.

[0086] Graphs of ln(Co/Ct) (where Co is the initial concentration of HOBr
and Ct is the concentration at time t) were plotted against time t. All
were close to straight lines (the regression analysis correlation
coefficient, R2 values were close to 1) for all three
NaOCl-activated HBr solutions. The R2 values for the 600 ppm, 300
ppm, and 50 ppm (expressed as Br2) solutions were 0.9302, 0.8156,
and 0.9352, respectively. From the lines, the half-life and decay rate
constants were determined. The half-lives were calculated by dividing the
slopes of the respective regression lines by 0.693--the natural logarithm
of 2. The slope of the respective linear regression lines indicated the
rate constant for HOBr decomposition (as Br2) at each concentration.
These figures are reported in Table 6.

[0087] These solutions did not undergo any significantly visible color
transitions during the activation of HBr. The endpoint was determined by
calculating the stoichiometric amount of NaOCl bleach required to
activate all the HBr. The equation below was used to determine the
maximum percent of bromide converted to HOBr (expressed as Br2).

[0088] In Table 6 above, the time correlating to the maximum conversion of
Br.sup.- ion to HOBr is displayed in parentheses under its respective
maximum percent-activated value. Based on this study, the lower boundary
concentration was defined as HOBr (50 ppm as bromine). At this
concentration, the half-life of the HOBr was adequate for storage up to
one day, and the conversion of HBr to HOBr was still high (94.73%). Any
lower concentration of HOBr than 50 ppm as bromine would be of little
practical value to use in a meat or poultry plant engaged in sanitizing
the animal carcasses, trim, and offal.

[0090] When HBr is activated with sodium hypochlorite bleach the resultant
hypobromous acid (HOBr) solution has long been considered by those
knowledgeable in the art to be too unstable for practical commercial use
(Howarth, U.S. Pat. Nos. 5,641,520 and 5,422,126). This example reports
the decay constants and the half-life for two concentrations of HOBr.
These were chosen to be above the lowest boundary condition of 50 ppm,
and below the upper boundary condition of 30,000 ppm (as Br2) (see
example 12). The purpose of this study was to provide an indication of
the persistency of hypobromous acid in the activated solution (expressed
as Br2). It also guides users of the time frame through which the
NaOCl-activated HBr solutions may be used without appreciable decay. An
additional objective of this example was to observe the change in pH of
the activated HBr solutions over time.

[0091] A low and a high concentration of activated HBr solutions were
employed in this study. The solutions were made by introducing sodium
hypochlorite bleach to the HBr and city water until the color transition
from dark orange to pale yellow was achieved, whereupon further addition
of NaOCl was discontinued. Once the HBr solutions were activated, an
initial pH and temperature were recorded and activity of HOBr was
measured using the iodometric titration (results expressed as Br2).
The activated solutions were stored away from direct UV light to prevent
photodegradation during the stability testing. The test was performed at
ambient temperature. The activities of the solutions were tested
periodically for 7-8 hours, along with recording the pH and temperature
of each solution. The temperature ranged from 74-80° F. for all
three studies.

[0092] The volumes used to prepare the high and low concentrations of HOBr
are displayed in Table 7 below. Throughout this example, the low
concentration HOBr solution (4800 ppm) is referred to as Solution 1 and
the high concentration HOBr solution (8620 ppm) is referred to as
Solution 2.

[0093] Hard city water was accurately measured out with a graduated
cylinder. The HBr 48% was measured using a graduated pipette and added to
the water. The solution was gently agitated before continuing. To
activate the HBr, a known concentration of sodium hypochlorite bleach was
added to the 48% HBr and water while gently mixing. The solution was
initially colorless. As the sodium hypochlorite bleach was added, the
color changed from colorless to bright yellow to a dark orange/red then
to a pale yellow. The pale yellow indicated that further addition of
NaOCl be discontinued. At this point, the pH of the activated solution
should be close to neutral. The color of the solutions slowly regressed
back to dark orange as time elapsed. The color regression occurred
because of the instability of HOBr. After the HBr solution was activated
with NaOCl, the time was recorded as zero minutes (T0) and samples
and readings were started.

Example 8

[0094]FIG. 3 illustrates the persistency of the HOBr (expressed as
Br2) for the low and high concentration solutions of activated HBr.
Solution 1 (low concentration HOBr solution) utilized 3.45 mL of HBr 48%
in 896.6 mL of city water and was activated with 19 mL of Bleach (9.29%
as Cl2). After the solution was activated, the activity tested at
4800 ppm as bromine, but due to the unstable nature of the HOBr, after
seven hours the activity decayed to 3692 ppm as bromine. Solution 2 (high
concentration HOBr solution) utilized 5.6 mL of HBr 48% in 844.4 mL of
city water and was activated with 25 mL of bleach (12.5% as Cl2).
Initially the solution generated 8620 ppm as bromine, but due to the
unstable nature of the HOBr, after eight hours the activity decayed to
4694 ppm as bromine.

[0095] The overview of the decay of HOBr with time provides users with a
tentative means to determine the activity of the NaOCl-activated HBr
solutions over time if the solution is not exposed to UV light. The
half-life of each solution is reported in Table 8.

[0096] The pH of the NaOCl-activated HBr solutions is driven by the decay
of HOBr. Therefore, the pH was observed while the HOBr decayed. Once HBr
is activated with sodium hypochlorite, the pH is between 7 and 7.8. The
pH drifts lower as HOBr decays according to the following equation:

2HOBr=O2+2HBr

[0097] In FIG. 4, the pH was tracked over the time span of the study for
both HOBr solutions. The initial pH of Solution 1, after activation, was
7.00 and after seven hours the pH dropped to 5.79. The initial pH of
Solution 2, after activation, with sodium hypochlorite bleach was 7.36
and after eight hours the pH dropped to 4.15.

[0098] A graph of ln(Co/Ct) for the HOBr solutions (where Co is the
initial concentration of HOBr and Ct is the concentration at time t) were
plotted against time t. The plot was close to a straight line (the
regression analysis correlation coefficients, R2 values, were 0.9492
and 0.9357 for Solutions 1 and 2, respectively). From these lines, the
half-lives and decay rate constants were determined. The half-lives were
calculated by dividing the slope of the regression lines by 0.693--the
natural logarithm of 2. The slope of the linear regression line indicated
the rate constant for HOBr decomposition

[0099] The half-lives for the decay of HOBr (expressed as Br2) in
Solutions 1 and 2 (calculated by dividing the slopes of the respective
regression lines by 0.692--the natural logarithm of 2) are displayed in
Table 8 below. The half-lives are reported in minutes and hours. Solution
1 has approximately twice as long a half-life as Solution 2.

[0100] The U.S. Food and Drug Agency (FDA) has approved the use of DBDMH
solutions containing a maximum of 300 ppm as Br2 for washing animal
carcasses (Food Contact Notification, no. 792). It is therefore predicted
that carcasses, trim, and offal washing or spraying with HOBr solutions
prepared by the NaOCl-activated HBr solutions will require a maximum of
300 ppm as bromine. When activating a low or high concentrated solution
of HOBr, as performed in this example, the solutions would need to be
diluted accordingly (depending on the concentration of HOBr utilized,
high or low concentration). The dilutions are to obtain a 300 ppm
(expressed as Br2) solution are displayed below in Table 9.

TABLE-US-00008
TABLE 9
Dilution factors
Original Concentration Dilution Factors (w/w)†
Solution 1 Must dilute by a factor of 15.6
(Low concentration HOBr solution)
Solution 2 Must dilute by a factor of 28.7
(High concentration HOBr solution)
†The dilution can be accomplished with a proportional dispenser or
with a separate diaphragm of centrifugal pump provided the volumetric
flow rates of the dilution water and NaOCl-activated solution are known.

Example 9

[0101] The microbiological efficacy of the HOBr derived from NaOCl/HBr and
the HOBr from DBDMH were compared against a culture of E. coli O157:H7
bacteria that was sprayed onto the surface of beef and pork meat.

[0102] Meat processing facilities commonly treat beef and pork with
antimicrobial solutions for about 30 seconds by spraying the beef and
pork carcasses and trim with the solution in a spray cabinet. To simulate
this process, a small spray cabinet was constructed for the study. A
30-gallon, open-headed drum was equipped with three 1/2 inch PVC section
of pipe that were vertically oriented and positioned 120 degrees apart.
Each section of pipe had two spay nozzles four inches apart positioned to
form a spray zone in the center of the drum. An air-assisted diaphragm
pump was used to deliver the test solution into the three 1/2 inch PVC
pipe sections and through the nozzles. A regulator on the air pump was
used to adjust the pressure of the spray as necessary.

[0103] DBDMH granules manufactured by Albemarle Corporation were obtained
from a local pool store. A saturated stock solution was made by mixing
the product in water followed by gravity filtration to remove any
undissolved solids. The stock solution was added to potable water in
order to obtain the appropriate concentration.

[0104] A 48% solution of HBr was obtained from Chemtura Corporation. For
this study, hypobromous acid (HOBr) was created on-site by combining
solutions of hydrogen bromide and sodium hypochlorite.

[0105] A stock solution of a field strain of E. coli O157:H7 was incubated
at 35° C. for four days in Sigma Nutrient Broth for microbial
culture. Three daily, consecutive transfers of the inoculums were made to
ensure that a sufficient concentration of E. coli O157:H7 was available
for the study. The broth and bacteria mixture was then centrifuged
leaving the E. coli O157:H7 to be re-suspended in approximately 500 ml
Butterfield's Buffer. The E. coli O157:H7 buffer solution was serially
diluted and plated on 3M Petrifilm E. coli plates, incubated at
35° C. for 48 hours where it was determined that the E. coli
O157:H7 population was 6.76×107 CFU/ml or log10 7.83.

[0106] The type of beef used was chuck roast, which was cut into nine
equal pieces. The average weight of beef piece used in this portion of
the study was 257.1 g. Nine boneless pork chops of average weight of pork
142.9 g were used.

[0107] Before spraying the meat, the concentration of HOBr in the
respective solutions was measured using a Hach DPD Total Chlorine
colorimeter, and the results expressed as ppm Br2.

[0108] This study performed in triplicate, i.e., three pieces of each meat
type was subjected to HOBr from NaOCl-activated HBr and from DBDMH for
comparison with a city water control.

[0118] During the 30 second spray, a piece of meat was held by a hook and
moved up and down in the spray zone of the spray cabinet with rotation to
ensure even distribution of the solution over the surface. The spray
pressure was set at 50 psi.

[0119] Immediately after each piece was sprayed, a sample of the wash
solution was taken from the bottom of the spray cabinet drum for
microbial analysis. The solutions were plated on 3M Petrifilm E. coli
plates and incubated at 35° C. for 48 hours.

[0120] After spraying, each meat piece was gently shaken three times to
remove excess liquid and returned to a new, sterile bag containing 200 g
of city water. The bag was sealed and then vigorously agitated manually
for one minute to dislodge any viable surface-associated bacteria from
the meat and into the aqueous phase. The water was then plated using 3M
Petrifilm E. coli plates and incubated at 35° C. for 48 hours,
after which the plates were enumerated. All plating for E. coli was
performed within five minutes of completing the spray.

[0121] The microbiological quality of the wash waters is summarized in
Table 10 where the two sources of HOBr are compared to that of a city
water control.

[0122] It can be seen that both DBDMH and NaOCl-activated HBr treatments
afford good reductions of bacteria present in the wash water. However,
the NaOCl-activated HBr displays a measurably higher efficacy than DBDMH.

[0123] The average concentrations of viable E. coli O157:H7 bacteria
remaining on both the beef and the pork after being sprayed with the
different sources of HOBr is compared to the amount remaining for just a
spray with city water in Table 11.

[0124] The same trend is apparent as was seen in the wash water; both
DBDMH and NaOCl-activated HBr treatments afford good reductions in the
number of surface-associated bacteria. However, the NaOCl-activated HBr
displays a measurably higher efficacy than DBDMH on both beef and pork.

Example 10

[0125] In the processing of poultry, birds that are deemed by the USDA
inspectors to have undesirable levels of fecal contamination are directed
to a dedicated cabinet where they are sprayed with an antimicrobial
solution. If the fecal contamination were not removed, birds harboring
the pathogenic Salmonella organism would enter the human food chain.
Therefore, the microbiological efficacy of the HOBr derived from
NaOCl/HBr and the HOBr from DBDMH were compared on chicken inoculated
with a culture of Salmonella typhimurium (ATCC 14028) bacteria.

[0126] DBDMH granules manufactured by Albemarle Corporation were obtained
from a local pool store. A saturated stock solution was made by mixing
the product in water followed by gravity filtration to remove any
undissolved solids. The stock solution was added to potable water in
order to obtain the appropriate concentration.

[0127] A 48% solution of HBr was obtained from Chemtura Corporation. For
this study, hypobromous acid was created on-site by combining hydrogen
bromide and sodium hypochlorite.

[0128] A stock solution of Salmonella typhimurium (ATCC 14028) was
incubated at 35° C. for four days in Sigma Nutrient Broth for
microbial culture. Three daily, consecutive transfers of the inoculums
were made to ensure that a sufficient concentration of Salmonella
typhimurium was available for the study. The broth and bacteria mixture
was then centrifuged leaving the Salmonella typhimurium to be
re-suspended in approximately 500 ml Butterfield's Buffer. The Salmonella
buffer solution was serially diluted and plated on 3M Petrifilm
Enterobacteriaceae Plates, incubated at 35° C. for 24 hours where
it was determined that the Salmonella typhimurium population was
2.34×108 or log10 8.37 CFU/ml (colony forming units per
milliliter).

[0129] Three whole, uncooked chickens were purchased from a local grocer.
The average weight of the whole chickens was 5.30 pounds. The organs were
removed from each chicken and subsequently, each chicken was cut evenly
in half down the back leaving six equal halves which contained a back,
breast, thigh and leg. The chicken halves were then patted dry with a
paper towel, sprayed liberally on all sides and marinated with Salmonella
typhimurium--Butterfield's Buffer solution inoculums for two hours,
turning occasionally.

[0130] The six chicken pieces were introduced to the spray cabinet used in
Example 9. This study was performed in duplicate, i.e., two chicken
halves were subjected to each test substance for 30 seconds. During the
30 second spray, a chicken half was held by a hook and moved up and down
while rotating to ensure even distribution of the test spray at 40 psi.
The concentration of HOBr was measured prior to spraying the meat pieces
by using a HACH DR/700 Colorimeter and HACH 10 ml DPD Total Chlorine
pillow packets.

[0131] In summary: [0132] a) Control: Two chicken halves--city water
[0133] b) DBDMH: Two chicken halves--295 ppm as total bromine [0134] c)
NaOCl/HBr: Two chicken halves--275 ppm as total bromine

[0135] After spraying, the chicken half was gently shaken three times to
remove excess liquid and returned to a new, sterile bag and taken to the
lab. 300 g of sterile city water was introduced to the bag and the bag
was vigorously shaken for one minute to dislodge viable
surface-associated Salmonella bacteria remaining on the chicken half.
This water was plated using 3M Petrifilm Enterobacteriaceae Plates and
incubated at 35° C. for 24 hours, upon which the plates were
enumerated. All plating for Salmonella was performed within 10 minutes of
completing the spray.

[0136] Table 12 reports the average number of bacteria left on the food
after being sprayed for 30 seconds with each challenge solution: city
water (control), DBDMH, NaOCl-activated HBr. It can be seen that the
control averaged a log10 of 6.15 CFU/ml. The chicken sprayed with
the DBDMH solution had a log10 reduction in Salmonella typhimurium
bacteria of 0.30 CFU/ml (49.88%). There was a log10 reduction of
0.34 CFU/ml (54.29%) when the chicken was sprayed with NaOCl-activated
HBr.

[0137] The same trend is apparent for chicken inoculated with Salmonella
typhimurium bacteria as was seen for beef and pork inoculated with E.
coli O157:H7 bacteria; although both DBDMH and NaOCl/HBr treatments
afford good reductions in the number of surface-associated bacteria, the
NaOCl-activated HBr treatment displays a measurably higher efficacy than
DBDMH.

Example 11

[0138] Most poultry processing facilities cool the product by submerging
it for 30-60 minutes in a chiller tank containing an antimicrobial
chemical. The chilled water solution is typically around 35° F.
(Food Contact Notification, nos. 334 and 453). Therefore, the
microbiological efficacy of the HOBr derived from NaOCl-activated HBr and
the HOBr from DBDMH were compared by immersing chickens inoculated with a
culture of Salmonella typhimurium (ATCC 14028) bacteria. An inoculum was
prepared in the same manner as described in Example 10. This time the
inoculum yielded a Salmonella typhimurium population of
3.78×108 CFU/ml, or log10 8.58. This was then sprayed
onto both sides of the chicken halves and left to marinate for two hours.
The average weight of the whole chicken used in this portion of the study
was 5.20 lbs.

[0139] Each test solution was made with chilled water immediately prior to
use. For each test solution and the control, two chicken halves were
placed in a plastic storage bin containing one quart of test solution. A
sterilized ice pack was placed in the bin to accompany the chicken and
maintain water temperature. The chicken halves were allowed to sit in the
chilled solution for 40 minutes at 35° F., and were turned every
five minutes while gently agitating the storage bin. All containers were
covered using aluminum foil to prevent degradation of the active
ingredients by UV light.

[0140] In summary: [0141] a) Control: Two chicken halves--city water
[0142] b) DBDMH: Two chicken halves--95 ppm as total bromine [0143] c)
NaOCl/HBr: Two chicken halves--100 ppm as total bromine

[0144] After spraying, each chicken half was gently shaken three times to
remove excess liquid and returned to a new, sterile bag. 300 g of city
water was introduced to the bag and the bag was tumbled vigorously for
one minute to dislodge viable surface-associated Salmonella bacteria. The
water left at the bottom of the bag was plated using 3M Petrifilm
Enterobacteriaceae Plates and incubated at 35° C. for 24 hours,
upon which the plates were enumerated.

[0145] Table 13 contains the average number of bacteria left on the food
after the 40 minute challenge test with each solution: city water
(control), DBDMH, and the NaOCl/HBr solutions. It can be seen that the
control averaged a log10 of 6.54 CFU/ml. The chicken submerged in
the DBDMH solution had a log10 reduction in Salmonella typhimurium
bacteria of 0.29 CFU/ml (48.71%). The chicken submerged in the
NaOCl-activated HBr solution had a log10 reduction of 0.50 CFU/ml
(68.38%).

[0146] For the immersed Salmonella typhimurium inoculated chicken, the
same trend is apparent as was for chicken that were sprayed; although
DBDMH and NaOCl/HBr treatments both afford good reductions in the number
of surface-associated bacteria, the NaOCl-activated HBr treatment
displays a measurably higher efficacy than DBDMH.

V. Compositions of HOBr

[0147] A third embodiment of the invention is a composition made by the
method of the first embodiment in which the concentration of HOBr is
greater than 20,000 ppm and less than 40,000 ppm (as Br2).

[0148] For efficient water management reasons, some animal carcass washing
facilities may elect not to prepare an RTU solution directly from HBr and
NaOCl bleach as described above. Instead they may wish to prepare a
concentrated product to be stored at a central point in the plant, then
dilute the product to several different concentrations to be used at
different Points-Of-Use (POU) areas of the facility (e.g., different
concentrations of HOBr may be required at the carcass wash, trim tables,
chiller tanks, on-line processing (OLR), off-line processing,
inside-outside bird washes (IOBW), the "hot box" spray where beef and
pork carcasses are hung for up to two days to bring their temperature
down, and incorporated into ice that animal carcasses or animal carcass
trim may come in contact with. Having a central storage point from which
the different concentrations of HOBr are prepared by dilution to the
required concentration represents a large convenience for the facility.

[0149] For these highly concentrated solutions of HOBr, it was therefore
considered necessary to define the optimum activation conditions in terms
of the % conversion of Br.sup.- ion into HOBr, the rate of the activation
reaction, and the storage stability of the resultant concentrated
activated solutions.

[0150] There are limits as to how concentrated a solution of activated HBr
can be made. Safety is one factor that would limit the concentration of
activated HBr. The activated solution would need to be prepared and
stored in a facility without releasing toxic bromine gas into the
atmosphere. Second to safety is the efficiency of conversion of the
bromide ions to HOBr, as this represents the major chemical cost and
hence the economics of the process. A desired process needs to have a
relatively high conversion of Br.sup.- ion into HOBr in order for the
solution to be economically practical. Therefore, the necessary boundary
conditions were determined for the use of HBr at the highest possible
limit. The boundaries set were determined from the data collected from
studies on HBr solutions of different concentrations that had been
activated with a sodium hypochlorite solution. This example defines the
highest boundary limit (which still has practical use in meat and poultry
processing facilities) for a HOBr concentrate that would be diluted down
to any desired concentration without posing a hazard.

[0152] The relative stability of HOBr (expressed as Br2) was compared
at three different high concentrations. The theoretical HOBr (expressed
as Br2) concentrations compared were 20,000 ppm, 30,000 ppm, and
40,000 ppm (expressed as Br2). The solutions were activated
separately by adding a stoichiometric amount of 48% HBr and sodium
hypochlorite bleach (of known concentration expressed as % Cl2) to a
known amount of city water to theoretically generate the desired
concentrations of 20,000 ppm, 30,000 ppm, and 40,000 ppm (expressed as
Br2). The HBr 48% was introduced to the known amount of city water
first. Using a magnetic stir plate, the solution was mixed gently until
homogenous. While mixing, a stoichiometric amount of sodium hypochlorite
bleach of known activity (determined by the iodometric titration) was
smoothly added to the solution. Any color transition was noted and the
final pH was measured.

[0153] The first concentration attempted was 40,000 ppm (expressed as
bromine). To activate this solution, city water (741.0 g) was weighed
into a liter beaker to which 48% HBr (38.04 g) was added. While mixing,
sodium hypochlorite bleach (13.24% expressed as Cl2) (120.96 g) was
smoothly added. This study was terminated after the bleach was added due
to the large amounts of toxic bromine gas released from solution and into
the atmosphere (fumes visible above surface of the solution). The pH did
not go higher than 6.45 and no color transition occurred (final color was
dark orange/red, not a bright yellow). The fact that the solution did not
turn bright yellow and that the pH did not exceed 7.0 indicated that the
HOBr decomposed too quickly to be of practical use, and that it would be
too unsafe to store in any facility due to the toxic bromine gas released
from solution and into the atmosphere.

[0154] The second concentration activated was a 20,000 ppm (expressed as
bromine) solution of NaOCl-activated HBr. City water (820.5 g) was
weighed into a liter beaker, to which 48% HBr (19.02 g) was added. When
the sodium hypochlorite bleach (13.24% expressed as Cl2), (72.31 g)
was added, the color transitioned to dark orange and then back to a
bright yellow indicative of activation. No bromine fumes were released,
so the decay profile was tracked. The activated solution was stored away
from direct UV light to prevent photodegradation during the testing. The
test was performed at ambient temperature. The solution was initially
tested using the DPD Differentiation Method (also known as the Palin
Modification) to confirm no chlorine was present after activation. After
proving no excess chlorine was present, the solution was analyzed using
the iodometric titration. The results were expressed as ppm as bromine.
The results were used to determine the percent bromide activated.
Tracking the decay profile of the activated solution followed this.

[0155] A graph of ln(Co/Ct) for the 20,000 ppm solution (where Co is the
initial concentration of HOBr and Ct is the concentration at time t) was
plotted against time t. The plot was close to a straight line (the
regression analysis correlation coefficient, R2 value was 0.9850).
From this line, the half-life and decay rate constant were determined.
The half-life was calculated by dividing the slope of the regression line
by 0.693--the natural logarithm of 2. The slope of the linear regression
line indicated the rate constant for HOBr decomposition.

[0156] The third concentration tested was 30,000 ppm as bromine. City
water (1039.4 g) was weighed out in a liter beaker, to which 48% HBr
(38.02 g) was added. When the sodium hypochlorite bleach (13.07%
expressed as Cl2) (122.54 g) was added the color transitioned to
dark orange and then back to a bright yellow and no bromine fumes were
released at first. The activated solution was stored away from direct UV
light to prevent photodegradation during the stability testing. The test
was performed at ambient temperature. The solution was only initially
tested using the DPD Differentiation Method (also known as the Palin
Modification) to confirm there was no chlorine present after activation.
Approximately 1 minute after activating the solution, bromine gas started
to be released from the solution as the HOBr decomposed. The sample was
tested 0.5 minutes after activation and the activity had already been
compromised by the rapid decay of the HOBr, therefore the decay rate was
too fast to track the decay profile so half-life and decay rate constant
data were unable to be measured. The figures for the three high
concentrations are summarized in Table 14 below.

[0157] In Table 14 above, the time correlating to the highest conversion
of bromide ion to HOBr (reported as Br2) is displayed in parentheses
under its respective percent-activated value. Based on the practicality
of the concentrations used in this study, the higher boundary was defined
as 30,000 ppm as bromine. At this concentration the half-life of the HOBr
was too short to be measure, but the conversion of HBr to HOBr was still
adequate (75.49%) to engineer around issues connected with controlling
the release of bromine fumes into the atmosphere, and allow time for the
solution to be diluted to a final use-concentration. Levels of HOBr
higher than 40,000 ppm would be would be of little practical value at a
meat or poultry plant engaged in sanitizing the animal carcasses, trim
and offal because of the inability to measure a meaningful % Br.sup.- ion
conversion to HOBr due to its rapid decomposition. Poor conversion of
bromide ions to HOBr is undesirable as this represents the major chemical
cost and hence the economics of the process.

[0158] When generating and storing a concentrated solution, similar to the
concentrations presented in this example, diluting to the
use-concentration is required. To make the concentrated solution to the
desired 300 ppm as bromine to spray or soak animal carcasses, trim and
offal, the concentrate activated solutions would need to be diluted
accordingly. Table 15 provides the dilution factors that would be used to
dilute a theoretical 20,000 ppm and 30,000 ppm (expressed as Br2)
activated solution of HBr to give a solution of 300 ppm (expressed as
Br2). These dilutions can be easily produced by either using a pump
to deliver the appropriate amount of activated solution to a known flow
rate of dilution water, or to use a dosing apparatus similar to that in
FIG. 1.

TABLE-US-00014
TABLE 15
Dilution Ratio to achieve 300 ppm (expressed as bromine)
NaOCl-activated HBrSolution
(Theoretical) Dilution Factors† (w/w)
20,000 ppm as bromine Dilute by a factor of 62
30,000 ppm as bromine Dilute by a factor of 76
†The dilution can be accomplished with a proportional dispenser or
with a separate diaphragm of centrifugal pump provided the volumetric
flow rates of the dilution water and NaOCl-activated solutions are known.

VI. Method of Reducing Fat, Oil, and Grease

[0159] Another embodiment of the invention is a method of reducing the
build-up of fat, oil, and grease on food contact and equipment surfaces,
and hard surfaces, such as floors, used in the processing of animal
carcasses, trim, and offal.

[0160] During the processing of animal carcasses, the meat products move
between the various processing stations via conveyor belts. Over the
course of a shift, layers of fat, oil, and grease can accumulate on the
belts, as well as on other equipment, and the floor. On floors these
layers represent a slipping hazard to employees whereas on food contact
surfaces the layers represent a safe harbor for potentially dangerous
microorganisms. Therefore, at the end of a shift, the equipment is
chemically cleaned of the layers of fat, oil, and grease to ready it for
the next shift. Fat is removed by saponification using highly alkaline
chemicals which can be expensive and hazardous. Oil and grease are
removed by emulsification with synthetic surfactants.

[0161] The antimicrobial solutions prepared by the method of the current
invention are near pH neutral, and contain no surfactants. Nevertheless,
these solutions have been found to exhibit surprising and remarkable fat,
oil, and grease solubilization properties. Not only do these solutions
have the advantages of reducing cleaning chemicals and clean-up times,
they are also effective against microorganisms concomitant in the fat,
oil and grease layers that accumulate on equipment, such as conveyor
belts, and other food contact surfaces, and on other hard surfaces, such
as floors.

[0162] One method of use in a meat or poultry plant during production
cycles that would be advantageous would be to use a continuous dip tank
or water spray containing the HOBr solution, which would help solubilize
and reduce the buildup of fats and oils on conveyor belts and equipment
which can harbor pathogenic microorganisms. A second benefit of this
method would be to decrease the cleaning time and chemicals used between
production shifts due to less contamination and microorganisms remaining
on the equipment during production periods.

[0163] In order to quantify the lipophilicity of HOBr solutions prepared
from NaOCl-activated HBr, the Octanol-Water Partition Coefficient was
determined. Further, since the HOBr from DBDMH is closely associated with
the organic DMH molecule which contains three carbon atoms, it was
expected that these solutions would exhibit even greater lipohilicity for
superior fat, oil and grease solubilization properties.

[0164] The Octanol-Water Partition Coefficient is defined as:

P ow = C octanol C water ##EQU00003##

[0165] Where:

[0166] Pow=Octanol-Water Partition Coefficient. Commonly the
logarithm of this number is reported as Log Pow

[0167] Coctanol=Concentration of solute in the octanol layer

[0168] Cwater=Concentration of solute in the water layer

Example 13

[0169] A high concentration of a HOBr solution was prepared by introducing
sufficient NaOCl to activate 3.34 ml 48% HBr in 900 ml RO water until the
pH was 7.23. By iodometric titration, the solution was determined to
contain 5625 ppm as Br2. The slightly yellow activated solution (25
ml) was poured into an Erlenmeyer flask containing octanol (25 ml). This
was mixed for two minutes using a high-speed magnetic stirrer after which
the two phases were allowed to separate. All of the yellow color had
phase-separated into the top octanol layer. Serial dilution followed by
use of the DPD total chlorine colorimetric method titration of the
aqueous phase revealed it to contain only 59.6 ppm as Br2. The
Pow was calculated to be 1.97. This was repeated for lower
concentrations of HOBr by preparing a stock solution of 300 ppm as
Br2 using 0.2 ml 48% HBr in 900 ml RO water and adding sufficient
NaOCl bleach until the pH was 7.33. From the 300 ppm as Br2 stock
solution, solutions of 200 and 100 ppm as Br2 were prepared.

[0170] Further octanol-water partition coefficient testing was performed
exactly as before. Table 16 summarizes the results.

[0171] A saturated solution of DBDMH was prepared by slurrying DBDMH (1 g)
powder in RO water (99 g) and stirring rapidly for 20 minutes.
Undissolved solids were removed by gravity filtration. By iodometric
titration, the solution was determined to contain 1170 ppm as Br2.
The DBDMH solution (25 ml) was poured into an Erlenmeyer flask containing
octanol (25 ml). This was mixed for two minutes using a high-speed
magnetic stirrer after which the two phases were allowed to separate.
Serial dilution followed by use of the DPD total chlorine colorimetric
method of the aqueous (bottom) phase revealed it to contain only 159.7
ppm as Br2. The Pow was calculated to be 0.808. The 1170 ppm as
Br2 stock solution was then used to prepare solution of 300, 200 and
100 ppm as Br2 solutions.

[0172] Further octanol-water partition coefficient testing was performed
exactly as before. Table 17 summarizes the results.

[0173] Comparing the data in Table 16 with that in Table 17 indicates that
the HOBr from NaOCl-activated HBr exhibits far more lipophilicity than
the HOBr from DBDMH. This is a surprising discovery because the HOBr from
DBDMH is closely associated with the organic DMH molecule, which contains
five carbon atoms and would be expected to partition into the organic
octanol phase to a greater extent than the HOBr from the totally
inorganic NaOCl and HBr sources. Thus, the enhanced lipophilicity of HOBr
from NaOCl/HBr compared to HOBr from DBDMH affords the former with
remarkably superior fat, oil and grease solubilization properties in meat
and poultry processing environments.

Example 14

[0174] The stability of the HOBr from NaOCl-activated HBr source that
partitioned into the octanol phase was determined.

[0175] A stock solution of HOBr was prepared by adding 48% HBr (3.45 ml)
to RO water (900 ml). Industrial-grade sodium hypochlorite (about 20 ml)
was added until the pH of the solution was 7.26. Iodometric titration
revealed the HOBr solution to be 3487 ppm as Br2. This solution was
designated the high concentration of HOBr. An aliquot (42 g) of this
solution was made up to 500 ml with RO water. This solution was
designated the low concentration of HOBr.

[0176] To each of the above solutions (200 ml), octanol (200 ml) was
added. The aqueous and the non-aqueous layers were vigorously mixed with
a magnetic stirrer whereupon the layers were allowed to phase separate.
The stability of the HOBr that had partitioned into the octanol phase was
assessed using a non-aqueous iodometric titration. In this technique, an
aliquot of the respective octanol phases was added to an aqueous phase
containing acetic acid and potassium iodide. With intense mixing of the
two phases, using the oxidation of iodide to iodine as the driving force
to partition the HOBr out of the octanol and into the aqueous phase, the
mixture was slowly titrated with 0.100 N sodium thiosulfate as a 1%
starch solution was introduced to sharpen the blue-to-clear end-point.

[0177] Non-aqueous iodometric titrations were performed for each solution
of HOBr partitioned into octanol. The results are summarized in Table 18.

[0178] It can be seen that for both high and low concentration of
octanol-partitioned HOBr, the HOBr is unstable and decomposes over the
course of 170 minutes. The HOBr is evidently decomposing due to its
oxidation of the hydroxyl group of octanol. Similar oxidation reactions
would occur when HOBr partitions into fats, oils and greases in meat and
poultry processing environments. This explains the remarkable fat, oil,
and grease solubilization properties that solutions of HOBr from
NaOCl-activated HBr have been discovered to possess.

VII. Methods and Compositions Employing Alkali Metal Bromides

[0179] Experimental Methods

[0180] Halogen levels were measured using N,N-diethyl-p-phenylenediamine
(DPD) spectrophotometric methods. For selective determination of
activated bromine, the glycine modification of the method was employed.
This required adding 2 ml of a 10% glycine solution to 98 ml of test
solution followed by use of the DPD-free chlorine indicator reagent. The
glycine binds any chlorine present as N-chloroglycine so that the
DPD-free chlorine indicator reagent response was solely due to the
presence of bromine in the sample. Addition of a few crystals of
potassium iodide to the test vial released any glycine-bound chlorine so
that the new DPD response was due to the sum of the halogen species
present.

[0181] Activation in a Residence Tank or Pipe Containing City Water

Example 15

[0182] Sodium bromide and sodium hypochlorite were independently
proportioned to a sample of city water from Modesto, Calif. to make a
concentrate of 1000 ppm HOBr/OBr.sup.- (expressed as Br2). The
laboratory simulation of this method of activation was accomplished by
introducing a 1:1 mole ratio of sodium bromide and sodium hypochlorite
bleach to the city water for dilution. The activated solutions were then
monitored for the next 2 to 2.5 hours to assess the time it took for the
maximum bromine concentration to be attained, the percent conversion of
Br.sup.- ion to HOBr/OBr.sup.-, the percent of total halogen recovered,
and the stability of the activated solutions.

[0183]FIG. 5 shows the actual ppm of HOBr/OBr.sup.- (expressed as
Br2) obtained over time when attempting to make a theoretical 1000
ppm activated solution by adding stoichiometric amounts of NaBr and NaOCl
to the city water. It can be seen that the maximum bromine concentration
was attained at 880 ppm at about 18 minutes, demonstrating that the
maximum biocidal benefit is not achieved until after that time. The
bromine concentration remained fairly constant for the next 132 minutes,
indicating that the activated solution remained stable over that period
of time. The pH of the activated 1000 ppm HOBr/OBr.sup.- (expressed as
Br2) solution was 9.57.

[0184]FIG. 6 plots the percent Br.sup.- ion activated to HOBr/OBrover the same time period. Only 77% of the Br.sup.- ion was activated
immediately. However, after 18 minutes almost 88% of the Br.sup.- ion was
activated, demonstrating an efficient utilization of the Br.sup.- ion.

Example 16

[0185] When the experiment of Example 15 was repeated to make a
theoretical 10,000 ppm HOBr/OBr.sup.- solution (expressed as Br2),
the maximum bromine concentration was attained at 8700 ppm at about 10
minutes, demonstrating that the maximum biocidal benefit is not achieved
until after that time. This is depicted in FIG. 7. The bromine
concentration in the activated solution remained fairly constant over the
next 170 minutes, indicating that the activated solution remained stable
over that period of time.

[0186]FIG. 8 plots the percent Br.sup.- ion activated to HOBr/OBrover the same time period. Only 75% of the Br.sup.- ion was activated
immediately. However, after 10 minutes, about 85% of the Br.sup.- ion was
activated, demonstrating an efficient utilization of the Br.sup.- ion.
The pH of the activated 10,000 ppm HOBr/OBr.sup.- (as expressed Br2)
solution was 10.81.

[0187] The data in Examples 15 and 16 show the surprising stability of the
1000 and 10,000 ppm HOBr/OBr.sup.- (expressed as Br2) activated
solutions. Contrary to the teachings of the prior art, the activated
solutions are not so unstable that they must be introduced to the
receiving water immediately before use, but rather are of sufficient
stability that they can be prepared, stored, and used later as needed.
The receiving water may be industrial cooling water that is treated with
sufficient activated solution to continuously dose the water to about 0.1
ppm (expressed as Br2). The receiving water may also be water used
to wash meat and poultry carcasses, trim, and offal that is treated with
sufficient activated solution to dose the water to between 200-900 ppm
(expressed as Br2). Finally, the receiving water may be water that
is treated with sufficient activated solution to dose it to 500 ppm
(expressed as Br2) and used to clean and sanitize food contact hard
surfaces and equipment.

[0188] Users who employ the method of activation described in Examples 1
and 2 may experience frequent CaCO3 scaling problems either in the
residence tank or in pipework leading to the water to be treated. The use
of NaOCl bleach will increase the pH of the city water used to make the
activated solutions. The pH was measured at 9.57 for the 1000 ppm
HOBr/OBr.sup.- (expressed as Br2) solution in Example 15 and 10.81
for the 10,000 ppm HOBr/OBr.sup.- (expressed as Br2) solution in
Example 16. Under practical conditions, high levels of calcium in the
city water will likely precipitate as CaCO3, which will accumulate
on surfaces, clog pipework, and lead to costly downtime for removal or
replacement.

[0190] This method avoids the use of dilution water (and hence scaling
problems). This method involves introducing neat, concentrated solutions
of sodium bromide and sodium hypochlorite into the opposite ends of a tee
fitting, and then piping the combined mixture into the cooling water to
be treated.

[0191] A mixture containing a 1:1 mole ratio of NaBr and NaOCl was
prepared by adding 20.02 g of aqueous 40% NaBr to 54.30 g NaOCl (10.66%
expressed as Cl2) solution. No additional water was used. The
mixture turned yellow, indicating that bromine had been generated. The pH
of the NaBr/NaOCl mixture was measured to be 12.86. Then the amount of
HOBr/OBr.sup.- generated in the mixture was measured by weighing a small
portion (0.08 g) into 20 L of synthetic cooling water of pH 8.8, followed
by using the glycine modification of the DPD colorimetric method
previously described. The stability of the HOBr/OBr.sup.- in the
activated solution was then tracked over the course of an hour. FIG. 9
charts the HOBr/OBr.sup.- content (expressed as Br2) and the
concentration of the activated solution (left hand y-axis). The same
curve also defines the percent activation of Br.sup.- ion into
HOBr/OBr.sup.- (right hand y-axis). It can be seen that about 84% of the
Br.sup.- ion was immediately activated. This maximized between 10 and 15
minutes where 97% of the Br.sup.- ion was in the form of HOBr/OBr.sup.-.
It can also be seen that the concentration of the activated solution was
not maximized until about 5 minutes, and remained stable until about 30
minutes. The concentration of the activated solution started to drop
after about 30 minutes.

[0192]FIG. 9 shows that the mixture prepared with a 1:1 mole ratio of
NaBr and NaOCl displayed surprising stability between about 5 and 30
minutes. Contrary to the teachings of the prior art, this activated
solution does not need to be introduced to the receiving waters
immediately, but is of sufficient stability that it may be prepared in
advance, stored, and used as required. This feature allows the user
sufficient time to build an inventory of activated solution so that the
inventory may be dosed to several different water systems requiring
treatment.

[0193] The receiving water may be industrial cooling water that is treated
with sufficient activated solution to continuously dose the water to
about 0.1 ppm (expressed as Br2). The receiving water may also be
water used to wash meat and poultry carcasses, trim, and offal that is
treated with sufficient activated solution to dose the water to about
200-900 ppm (expressed as Br2). Finally, the receiving water may be
treated with sufficient activated solution to dose it to about 450 ppm
(expressed as Br2) and used to clean and sanitize food contact hard
surfaces and equipment.

Example 18

[0194] To demonstrate the utility of the activated solution for typical
cooling water, a small amount was introduced to a synthetic cooling water
prepared with the water quality characteristics shown in Table 19.

[0195] To obtain a theoretical dose of 2.0 ppm HOBr/OBr.sup.- (expressed
as Br2), the mixture (0.404 g) was immediately introduced to 20 L of
synthetic cooling water in a five-gallon pail that was stirred with an
overhead mixer.

[0196] The ambient temperature treated cooling water was immediately
subjected to DPD analysis to determine the same efficiency parameters as
before. Because 1.7 ppm of HOBr/OBr.sup.- (expressed as Br2) was
immediately recovered, only 85% of the Br.sup.- ion was immediately
activated. However, as FIG. 10 shows, the HOBr/OBr.sup.- in the cooling
water was not particularly stable and decomposed to just 1.06 ppm of
HOBr/OBr.sup.- (expressed as Br2) after 4.5 hours, corresponding to
a 53% conversion of the initial bromide. This degradation profile is
shown in FIG. 10.

Example 19

[0197] Many users employ more than a 1:1 mole ratio of NaBr to NaOCl in
the belief that in the bulk recirculating cooling water the excess NaOCl
reactivates the Br.sup.- ion that is the degradation product of
HOBr/OBr.sup.-. This was investigated in another experiment in which the
mole ratio of NaBr to NaOCl was increased to 1:2 and the cooling water
was dosed with sufficient mixture to achieve a theoretical 4 ppm of
HOBr/OBr.sup.- (expressed as Br2). FIG. 11 plots the HOBr/OBrgeneration and stability profile over a three-hour period.

[0198] It can be seen for the 1:2 NaBr:NaOCl mole ratio that the
HOBr/OBr.sup.- appears to be far more stable than for the 1:1 mole ratio
as seen in FIG. 10. However, the trend can be explained by the data in
FIG. 11 which plots the percent "apparent" Br.sup.- ion activated to
HOBR/OBr.sup.- and the depletion of the excess chlorine over the same
time period. At the higher NaBr:NaOCl mole ratio the percent conversion
of Br.sup.- ion is over 93% within one minute of the activated solution
being introduced to the cooling water. The depletion of the excess
chlorine mirrors the regeneration of HOBr/OBr.sup.- as the percent
"apparent" Br.sup.- ion conversion increases to 124%. The appearance that
the stability of HOBr/OBr.sup.- is improved at the higher NaBr:NaOCl mole
ratio is simply due to the fact that the excess NaOCl is reactivating the
Br.sup.- ion degradation product.

[0199] The utility of activated solutions prepared with NaBr:NaOCl mole
ratios of up to 1:2 to treat water that is used to wash meat and poultry
carcasses, trim, and offal for the reduction of pathogenic microorganisms
is demonstrated by the following example.

Example 20

[0200] The efficacy of an activated solution of HOBr/OBr.sup.- ion was
investigated against a culture of pathogenic microorganisms that had been
sprayed onto pieces of meat.

[0201] A stock solution of E. coli O157:H7 (ATCC 35150) was incubated at
35° C. for two days in Sigma Nutrient Broth for microbial culture.
One daily transfer of the inoculum was made to ensure a sufficient
concentration of E. coli O157:H7 was available for the study. The broth
and bacteria mixture were then centrifuged leaving the E. coli O157:H7 to
be re-suspended in approximately 500 mL Butterfield's buffer. The E. coli
buffer solution was serially diluted and plated on 3M Petrifilm E. coli
plates. The plates were incubated at 35° C. for 24 hours, at which
point it was determined that the E. coli O157:H7 population was
6.0×107 or log10 7.78.

[0202] The lean beef used in this study was boneless top sirloin. The meat
was cut into six equal pieces that averaged a weight of 78.4 g. Each beef
piece was evenly sprayed with the E. coli Butterfield's solution and
allowed to soak.

[0203] An activated solution of HOBr/OBr.sup.- was prepared using a 1:1
mole ratio of NaBr:NaOCl in the absence of dilution water. Thus, 40% NaBr
(20.06 g) was added to NaOCl bleach (12.94% as Cl2) (42.73 g).
Iodometric titration of the mixture revealed it to have a halogen content
of 19.84% as Br2 and it had a pH of 12.18. Two minutes were allowed
to pass in order to maximize the activation of Br.sup.- into
HOBr/OBr.sup.-. Then the sample was shielded from light with a cover and
then set aside and stored for 15 minutes.

[0204] After 15 minutes, the activated solution of HOBr/OBr.sup.- (4.54 g)
was added to city water (1000 mL) of pH 7.8. Analysis using the modified
DPD method indicated that it contained 918 ppm of HOBr/OBrexpressed as Br2 and that chlorine was absent. Due to the high pH of
the activated HOBr/OBr.sup.- solution, the city water to which it was
added now had a pH of 9.93. In order to lower the pH to be more like the
pH of city water, 32% hydrochloric acid (HCl) (0.59 g) was introduced to
give a solution with a pH of 7.86.

[0205] Four of the E. coli O157:H7 inoculated cuts of boneless top sirloin
were then evenly sprayed with the 918 ppm as Br2 test solution and
allowed to sit for 15 minutes. At the same time, as a control, two of the
E. coli O157:H7 inoculated cuts were sprayed with city water that had not
been treated with activated HOBr/OBr.sup.-.

[0206] After 15 minutes contact time, each piece of beef was placed in a
sterile poultry rinse bag containing 100 g of city water. Each bag was
held closed and then vigorously tumbled for one minute in order to
dislodge viable surface-associated E. coli bacteria into the aqueous
phase. This water was then sampled and plated onto 3M Petrifilm E. coli
plates. All plating was completed within 30 minutes of spraying the
pieces of beef with the activated HOBr/OBr.sup.-. The plates were then
incubated at 35° C. for 24 hours, after which the plates were
enumerated.

[0207] Table 20 reports the average number of viable surface-associated E.
coli O157:H7 bacteria dislodged from the beef pieces into the tumble
water.

[0208] It can be seen that the untreated city water control averaged a
log10 of 5.66 E. coli O157:H7, while the acidified activated
HOBr/OBr.sup.- treated beef pieces averaged a log10 of 4.85 E. coli
O157:H7. The log10 reduction in E. coli O157:H7 bacteria using the
acidified HOBr/OBr.sup.- solution was 0.81 CFU/mL corresponding to a
reduction of 84.5%.

[0209] Despite being sprayed with a high concentration (918 ppm as
Br2) of acidified, activated HOBr/OBr.sup.- solution, none of the
beef pieces exhibited any sign of bleaching or discoloration.

[0210] The invention has been described above with the reference to the
preferred embodiments. Those skilled in the art may envision other
embodiments and variations of the invention that fall within the scope of
the claims.